I'm thinking about instalilng a fm modulator in my bonneville, and i'd like it so that the only times it can get power are pretty much when the radio is on, like on acc, and shut off when i shut the car off........where can i get the 12V power from for my modulator? in the fuse box? or cigarrette lighter?

I thought that too, but I wired my angel eyes to it, and there'* no difference whatsoever. The angel eyes draw such little power though. I'm not sure if the modulator would take noticeable power away from the radio.

There are tons of good sources at the fusebox. Usually intended for possible options that weren't installed. A quick test with a multimeter and a couple flicks of the key will tell you which ones are switched.